Multiple plug connector



E. J. GLENNON MULTIPLE PLUG CONNECTOR May 19, 1942.

Filed Sept. 23, 1940 Patented May 19, 1942 2.283.498 MULTIPLE PLUGcormnc'roa Edward Joseph Glennon, Chicago, 111., assignor to ComarElectric 00., Chicago, 111., a corporation of Illinois ApplicationSeptember 23, 1940, Serial No. 357,840

8 Claims.

I This invention relates to electrical plug-in connectors especially thevariety adapted to have a plurality of electrical conductors or wiresconnected thereto for plug-in connection to other conductors connectedwith terminals in a receptacle or terminal strip.

An object of the invention is to provide an improved connector of thisclass which will be simple in construction, r ged, yet smooth andpositive in operation and adapted to prevent errors in effecting theunion of the complementary connecting elements. Y

A further and more particular object is the provision of a connectingplug consisting of complementary members one of which includes aplurality of plug connectors and the other of which includes a similarnumber of spring clip plug receptacles, together with means forming apart of the frame for one of the complementary members adapted to guidethe other member into a predetermined assembled relationship therewithand prevent reversal of said other member in fitting the plug-incontacts into' the receptacle.

A further object is the provision of a multiple connector consisting ofa terminal strip, having a plurality of spring clip connectors, and aplug strip having a plurality of connecting plugs adapted to fit intothe clips when the two strips are brought together, one end of the plugstrip being provided with a cable-tying formation and the opposite endof the terminal strip being provided with a guide member, engageablewith the cable-tying formation to prevent bringing the complementaryconnector members or strips together in reverse relationship, the guideformation otherwise being adapted to bear against the end of the plug-instrip opposite the cable-tying formation to facilitate insertion of theconnecting plugs into the spring clips or receptacles.

A still further objection relates to the provision of improved female orspring clip receptacles and means for mounting the same between twoinsulated strips constituting the principal part of the terminal strip,an additional object in this respect relating to the provision ofoppositely punched spring fingers on the clips or plug receptacles, thefingers being curved concavely to bear in self-cleaning, scrapingengagement with the connecting plugs.

Yet another object relating to the spring contact fingers relates to theprovision of a curvature at certain end parts thereof for initialengagement with the connector plugs to effect an easy and quickinsertion of the latter.

A further important object relates to the provision of certain guidingformations on the male or plug-in connectors and adapted to co-act withopenings leading into the spring clip receptacles as well as with thespring finger formations themselves to effect a positive and firmconnection.

A still further object is the provision of certain cut-away formationson the metal frame parts of the terminal strip adapted to preventengagement with the contact plugs on the complementary strip when thelatter is rocked while in position on the terminal strip whereby toprevent short circuiting.

A further object is the provision of a spring contact jack formed from aunitary metal strip bent back upon itself with opposite presser fingersconnected to the strip at opposite ends of the jack (with respect to aplug inserted therein) to shorten the electrical path and lower theresistance of a circuit therethrough.

Other objects, advantages and novel aspects of the invention reside incertain details of construction as well as the cooperative relationshipof thecomponent parts of the illustrative embodiment describedhereinafter in view of the annexed drawing, in which:

Fig, 1 is a side elevation of the complementary conductor members withthe. plug strip rocked out of normal position.

Fig. 2 is a fragmentary end perspective of the complementary conductorsand the guiding means for preventing reverse connection.

Fig. 3 is a transverse section along lines 3-3 of Fig. 2 showing thespring fingers on the female or jack receptacle or connectors.

Fig. 4 is a horizontal section along lines 4-4 of Fig. 3 showing theself-cleaning scraper formations on the spring contact fingers, th'e viebeing to an enlarged scale.

Fig. 5 is a horizontal section along lines 5-5 of Fig. 1 showing partsof the terminal conductor strip and elevation.

t1;ig. 6 is a bottom-plan view of the terminal s r p.

Fig. 7 is a fragmentary end perspective of the plug-in strip showing thecable-tie.

Fig. 8 is an enlarged perspective detail of a special testing plug andcomplementary guiding formations on the terminal strip.

In Fig. 1 the terminal strip is generally indicated by the referencecharacter In while the complementary or plug-in strip is generallyindicated at H.

As seen in Fig. 2 the terminal strip consists of upper and lowerinsulated strips l2 and I3 clamped together by peened over portion Ivide an outer end portion'constituting a lug 2| which fits snugly into acorresponding slot 22 formed along edge of the lower insulated strip IS,the two strips having aligned openings I 5 and |3a above each jack orspring clip and the latter being provided with a portion 23 which isclamped between the upper and lower strips and then extends downwardlythrough the aligned opening Na and is bent back upon itself to provide abight portion, which is turned upwardly through the opening |3a againwith an end portion '25 turned over and clamped between the upper andlower insulated strips. There are as many jack or spring clipconnectors. as desired, the same preferably being arranged in pairs onopposite sides of the .terminal strip assembly, that is to say onopposite sides of the reenforced cross-bar IS.

The plug-in connector strip consists of a single thickness or strip 28(Figs. 2 and 3 particularly) having a plurality of punched openings 21therein adapted for alignment with the openings l2a in the terminalstrip, and there being a plurality of substantially rigid plug-inconnector fingers 28 arranged on the strip 28 so that each extendsthrough one of the openings 21 with the upper portion 28a bent over andriveted as at 28 to the strip 26, each of said bentover portions havingan upwardly projecting lug part 38 provided with an eye portion forsoldered connection with a conductor 8| as illustrated in Fig. 7.

Since a plurality of conductors 3| must be led into position adjacentcorresponding connecting plugs 28-88 on the strip 26, the conductors arepreferably made up into a cable generally indicated at Ma in Fig. 7 andthe cable is led unto the plug-in connector strip 28 along the centerthereof between the opposite rows of lugs 30 and the several individualconductors 3| branched of! at convenient intervals for connection withtheir respective lugs.

A special feature of the improved connector assembly resides in theprovision of a cable-tie at one end of the plug-in strip, this tie beingformed in the .arrangement shown by cutting opposite notches 32 near theouter end of strip 26 so as to form a cross-piece or T-head 38 in thenature of a tail, which is alsoof importance in cooperation with certainguide means hereinafter to be explained. Means such as the waxed cord 34may be engaged in the notches 32 around cable 3ia to secure the latterfirmly in position on plug-in connector strip.

In order to facilitate the plug-in of the member II in the terminalstrip Hi, there is provided guide means in the form of an upwardprojection Me on the bracket or foot [8, this projection being adaptedto abut the end part 28a (Fig. 2) of the plug-in strip when the latteris positioned properly above the terminal strip ready for insertion ofthe plugged portions 28 in the correspondingly aligned holes |2a of theterminal strip. By the simple act of placing the end 28a deliberatelyagainst the guide proiection "a, it will be assured that the plug-inconnector strip is in the proper longitudinal position relative to thecomplementary strip or connectors, and the possibility of reversing theconnec-' tion is wholly prevented because the T-head projection or tail33 at the opposite end of the plugin connector strip would engage theend of the guide projection I81: and prevent seating the plug-inconnecting strip on the terminal strip.

A further feature of the invention relates to the formation of thespring contact fingers 28a and 20b on the jack or spring clipconnectors, it being apparent from Fig. 3 that these fingers are sprungor biased toward each other from 5 opposite juncture points 28c and 28don opposite whereby opposite marginal edge portions 20;; are

provided on each finger for scraping engagement with the surface of theconnector plugs 28, thus assuring good electrical contact. Moreover aswill appear from examination of Fig. 5, the opposite disposition of thejuncture portions 28c and 20d of the fingers on each spring clip causesthe fingers to bear against the plug 28 at vertically spaced points asclearly seen in Fig. 5, which tends to rigidify or stabilize the seatingof the plug in its corresponding jack.

Since it is frequently desirable to insert individual connector plugs inany of the jacks or receptacle openings for purposes of makingtestconnections or the like and since such single plugs do not have therigidifying reenforcements of a mounting strip such as the plug-inconnector strip 28, they commonly wiggle while in position and workloose or at best provide a poor electrical connection. To overcome suchobjectionable characteristics, the terminal strip or jack connectionsare especially designed as to the formation of the holes or plugopenings He in the upper terminal-strip l2, these openings l2a, as shownto enlarged scale in Fig. 8 being conveniently characterized as having adumbell shape." In other words, the openings are keyed, being ofrectangular form with opposite central projection l2b.

The special plug consists of a thin strip of metal bent back upon itselfat its mid-portion 88 and having lug formations 31 aligned at itsopposite ends with an intermediate curvature or bulge 38 adapted torigidity the plug and also permit a degree of yieldability in the mainplug portions 38 upon insertion and withdrawal from the jacks. Oppositelongitudinal edge portions of the strip on opposite sides of the bightportion fitting closely a ainst the main portions 39 of the plugs betwen the flanged portion 40 thereof for positive and firm mechanical andelectrical engagement.

It frequently happens that the plug-in connector H will accidentally ordeliberately be rocked in the manner illustrated in Fig. 1 and in priordevices of this kind opposite plugs would bear against the metal of theend leg or bracket [9 and cause a short circuiting. To avoid this theend leg or bracket 19 of the improved terminal strip has a specialcut-away portion indicated at Na in Figs. 1 and 5, so that the lower endportion 28a of the plugs will always clear the bracket, the form andextent of such cut-away portions being calculated in a definite relationto the length of the plugs 28 and distance of the nearest jack orterminal strip opening from bracket H! to assure such clearance, thedimensions varying with changes in size and number of connections foreach individual connector assembly.

It should also be observed from Fig. that flat plug 28 is engagedrespectively by the oppositely attached fingers c and 20d so as toprovide a shortened electrical path in the nature of a by-pass or shuntaround the main bend or bight portion 20 of the jack. Such reduction ofterminal resistance is important, especially for current values fromabout one-quarter ampere upwards.

The preferred embodiment of the invention set forth herein has beendescribed in detail for purposes of illustration, it being understoodthat the objects of the invention may be accomplished by other forms andarrangements of the specific means set forth, so that the invention isnot to be limited to any precise details of form, location, or functionexcept as may be provided hereinafter in the appended claims.

I claim:

1. In a device of the class described means providing a terminal jackconnector including a pair of insulated strips provided with registeringopenings, a spring clip jack associated with each pair of registeringopenings, each jack consisting of a thin metal strip bent back uponitself with opposite end portions clamped between said insulatingstrips, and further provided with a pair of mutually biased pressercontact fingers one of which is attached to the jack adjacent the bendthereof, while the other is attached at its end remote from said bend toprovide a shortened electrical path around said bend, said fingers beingdisposed beneath the corresponding pair of openings to bear againstopposite sides of a connector plug.

2. The device of claim 1 further characterized in that said contactfingers of each pair are concaved transversely of their length toprovide opposite longitudinal contact edges engageable with the sides ofsaid plug to provide a positive electrical and mechanical contacttherewith, said plug being flat for positive surface contact with saidedges.

3. In a connector plug of the class described including an elongatedplug member for insertion in a jack, the combination of a jack in theform of an elongated metal strip bent back in a direction upon itself toprovide oppositely spaced side portions Joined by a bight portion, oneof said side portions having a contact finger punched out therefrom withan end portion attached to said side portion at a point spaced away fromsaid bight in the direction of length of said jack, the remaining saidside portion having a contact finger punched therefrom with one endportion attached to said remaining side portion at a point adjacentlynear said bight in the direction of the length of said jack, wherebysaid plug when received in said jack will be engaged by said contactfingers on opposite sides thereof in a manner to provide an electricalshunt path leading around and in electrical parallel with said bightportion, for the purpose of lowering the electrical resistance of acircuit through said jack and plug.

4. In a connector plug, the combination, with a plug having oppositefiatsurface portions, of a jack having opposite spring presser fingersdisposed to bear against said fiat surface portion respectively, saidfingers being concaved toward said surface portion to provide oppositecontact edges bordering the concaved portion whereby eachfinger hasopposite edge portions contacting the corresponding fiat surfaceportions of the plug to provide a scraping electrical contact.

5. In a connector, a jack type contact consisting of a piece of metalbent back upon itself to provide opposite arms, each of said arms havinga presser finger punched therefrom so as to remain attached near one endthereof to the corresponding arm, the end of attachment of one saidfinger being opposite from that of the other, whereby to provide ashortened electrical path through said fingers in engagement with a plugconnected in said jack.

6. In a connector, a receiving contact structure for aplug-in contact,said structure including a conductive strip having a U-shaped portionincluding opposite side arms joined by a connecting bight portion, onesaid arm having a pressure finger attached thereto at a point relativelynear said bight portion to project in the general direction of length ofthe corresponding arm; and the other said arm having a similar presserfinger distinguished by being' attached to its said arm at a pointremoved from said bight portion by .the distance of the length of saidfinger.

7. In a connector, in combination, a fiat, elongated, contact plug, anda jack therefor including opposite side arms between which said plug isadapted to fit, each said arm having a presser finger extending in thegeneral direction of length of said plug, each said finger beingattached at one of its ends to its respective arm, and the attachment ofone finger being at an end thereof which is opposite from that of theother finger.

8. In a connector, 9. contact finger of approximately elongated formadapted to engage a complementary elongated contact having substantiallyfiat contact surface portions and to engage and disengage with saidcontact finger by movement in the direction of length of itself and thefinger, said finger having opposite longitudinal edges turned generallytoward each other out of the plane of the remaining body portionsthereof to present scraping contact edges engageable with said flatcontact surface portions of said complementary contact.

EDWARD J. GLENNON.

